Handy online tools for work and life
Health calculators, developer utilities, math helpers and more — 40+ tools that run entirely in your browser. No sign-up, no uploads, your data never leaves your device.
Runs in your browser12 Languages10 Themes
BMI CalculatorEnter height in cm and weight in kg to get your Body Mass Index via the Quetelet formula, with underweight-to-obese categories and your healthy weight range.Body Fat CalculatorPick gender and enter age, height, weight plus waist, neck and hip to estimate body fat with the US Navy method and the Deurenberg formula side by side.Sleep Cycle CalculatorEnter your wake-up time and get bedtimes for 4 to 6 full 90-minute sleep cycles, minus 15 minutes to fall asleep, so you wake at the end of a cycle and avoid sleep inertia.Calorie CalculatorType in grams of protein, carbs and fat to convert them to kilocalories with the 4-4-9 Atwater rule, plus a quick reference table of food calories per 100 g.BMR CalculatorEnter gender, age, height and weight to compute your basal metabolic rate with the Mifflin-St Jeor formula, then your daily burn at light, moderate and high activity.Ideal Weight CalculatorEnter gender and height to compare the classic Devine, Robinson and Miller formulas side by side, plus the healthy BMI weight range for your height.Water Intake CalculatorEstimate how many millilitres of water an adult should drink each day from weight, activity level and hot-weather factor, split into morning, noon and evening sips.
Learn to Tell TimeA beautiful teaching clock for kids: explore the dial and hands, set any time with sliders, then practice o’clock, half-past, 5-minute and any-time quizzes.English Case Converter — 12 Naming StylesConvert any English text into 12 naming styles at once: UPPER, lower, Title Case, camelCase, PascalCase, snake_case, kebab-case, CONSTANT_CASE, dot.case, alternating and swap case, with live character count and one-click copy.Unit ConverterConvert length, weight, temperature, area, volume, speed, time and data units instantly as you type, with no lookup tables.Age CalculatorGet your exact age in years, months and days, the countdown to your next birthday, plus your Western zodiac sign and Chinese zodiac animal.Text Case ConverterTurn text into uppercase, lowercase, start case, sentence case, reversed, trimmed and spaceless all at once, with live preview and one-click copy.QR Code GeneratorCreate a QR code from any text or link, choose size and error correction level, preview live and download a high-resolution PNG, free with no watermark.Timestamp ConverterLive Unix timestamp in seconds and milliseconds, with bidirectional conversion between timestamp and local date and time, for developers.Random Password GeneratorBuild strong random passwords with your chosen length and character sets, filter out ambiguous characters and read the live strength meter, then copy in one click.Random Number GeneratorDraw true random numbers in a min to max range, with count, allow duplicates or not, auto-sort and a history list, great for draws and lotteries.Countdown TimerCount down to a target date and time or a set duration, live in days, hours, minutes and seconds, with pause, resume and reset, for birthdays, exams and events.Color ConverterConvert between HEX, RGB, HSL and HSV live, pick colors with a color picker and copy each format value in one click, for web design.Color MixerBlend two or more colors into one by averaging their RGB channels, add up to 8 colors, watch the result live, copy or download.Color Overlap & WheelThree-circle color overlap: additive RGB on black and subtractive HSB on white, plus a 360° hue wheel to pick any color.Space NormalizerCollapse multiple spaces inside text into exactly N (default 1) and control how many spaces to keep at start and end.Invisible Character Tool — Strip & InjectDetect and strip hidden invisible characters (zero-width space, BOM, soft hyphen, directional marks) from pasted text, or inject them at random positions. One-click copy and PNG download.Text SorterSort any text by letters — ascending, descending or shuffled — with optional ignore-case and dedupe, live character counts and one-click copy.Text Find & Replace ToolText Find & Replace is an efficient text-processing tool that finds specific content in any text and replaces it in one batch. Paste your original text, enter the find and replace strings, then press Confirm — everything runs locally and privately. It features live preview: matches are highlighted with the theme color while searching; when replacing, removed text is struck through in red and inserted text is shown in blue, so changes are clear at a glance. Advanced options include ignore case (on by default), match whole words only, and regular expressions (opt-in), covering copy editing, coding, data cleaning and content tidying. The result panel shows the processed text with its character count, ready to copy in one click or download as an image with the brand footer. Every confirm is saved to local history (up to 10 entries) with per-entry copy, per-entry delete and clear-all for easy review. Clean and beautiful UI with light/dark themes and 12 languages — a handy little helper for everyday text work.World Clock — Live Time ZonesAn interactive world time map: 24 equal time-zone strips, live clocks for the world's major cities, add any city by IANA timezone, all stored locally.
Base ConverterConvert integers between binary, octal, decimal, hexadecimal and any base from 2 to 36, using digits 0-9 then letters a-z, with a live common-base reference table.Base64 Encoder / DecoderEncode text to Base64 and decode it back through UTF-8 bytes so Chinese, emoji and other Unicode characters survive the round trip, with copy and result feedback.URL Encoder / DecoderPercent-encode and decode URLs and query parameters in both encodeURIComponent and encodeURI modes, correctly escaping Chinese and spaces, with friendly errors on malformed sequences.HTML Entity Encoder / DecoderConvert characters to and from HTML entities: named ones (amp, lt, gt, quot) and numeric hex entities, with non-ASCII auto-escaped and a per-character mapping table.Unicode Escape Encoder / DecoderConvert characters to and from uxxxx escapes, splitting emoji and other supplementary-plane characters into correct surrogate pairs, with per-character code point, UTF-8 bytes and UTF-16 units.UUID GeneratorGenerate RFC 4122 version-4 UUIDs locally in the browser with crypto.randomUUID, from 1 to 20 at a time, uppercase or lowercase, hyphens optional, copy one or all.QR Code GeneratorGenerate a QR code from any text, link or phone number, with adjustable size, margin, error-correction level and foreground or background colors, live preview and one-click HD PNG download.Password GeneratorGenerate strong random passwords locally in the browser, length 4 to 128, with selectable upper or lower letters, digits and symbols, live entropy and strength rating, up to 10 at once.JSON FormatterFormat, minify and validate JSON in the browser, pretty-printing with two-space indentation, pointing at the exact line, column and snippet on error, with object and array structure stats.Character CounterCount characters with or without spaces, words, lines, paragraphs and UTF-8 bytes live as you type, with built-in targets like Weibo 140 or Twitter 280 and a remaining-characters counter.Hash GeneratorCompute MD5, SHA-1, SHA-256, SHA-384 and SHA-512 digests of text or a local file live, with one-click copy and uppercase toggle, for file checksums and integrity verification.Regex TesterTest regular expressions live with match highlighting and hit count, capture groups shown per match, flags global, case-insensitive, multiline and more, plus built-in email and phone examples.Markdown PreviewWrite Markdown on the left and render it live on the right, with GFM tables, fenced code blocks and strikethrough, plus a view and one-click copy of the generated HTML source.Case ConverterConvert any text to eight casings at once: UPPERCASE, lowercase, Title Case, sentence case, camelCase, PascalCase, snake_case and kebab-case, each with its own copy button.
CalculatorA pocket-style immediate-execution calculator on screen: type on your keyboard or tap the keys, chain add-subtract-multiply-divide, use percent and sign toggle, with a friendly divide-by-zero message.Scientific CalculatorAn online scientific calculator with sin cos tan and inverse trig, ln/log logarithms, powers, square root and factorial, plus constants pi and e, with degree-radian mode for students and engineers.Long DivisionEnter dividend and divisor as whole numbers and watch long division replay step by step: each quotient digit, the product subtracted and the running remainder, with 2, 4 or 6 decimal places and recurring-decimal detection.Fraction CalculatorEnter the numerator and denominator of two fractions to add, subtract, multiply and divide them. Results auto-reduce to lowest terms, toggle between improper and mixed numbers, with decimal and percentage shown alongside.Time CalculatorPick two date-times and instantly get the gap in days, hours, minutes and seconds plus total seconds; or add or subtract a duration in days-hours-minutes-seconds to a start moment.World ClockLive clocks for UTC and eight major cities — Beijing, Tokyo, Sydney, Dubai, Paris, London, New York and Los Angeles — plus a UTC-offset converter to compare every city.Percentage CalculatorOne tool for three percent questions: what is p percent of x, what percent x is of y, and the percent change from x to y. Clear formulas and instant results for discounts, shares and growth rates.Date DifferencePick two dates and get the total days, total weeks and a year-month-day combo at once, then add or subtract N days or months from a start date. Leap years handled, great for age and project duration.Loan CalculatorEnter the principal, annual rate and term in months to compare equal installment annuity against equal principal side by side: monthly payment, total interest, total repayment, plus an amortization schedule.
